1. Field of the Invention
The present invention relates to a soldering flux composition suitable for use in, for example, soldering.
2. Description of the Related Art
In conventional soldering fluxes, freon or the like is used as a cleaning solvent for cleaning away any flux remaining after the soldering, but nowadays the environmental destruction caused by flon has become a serious issue, and a solution to this issue is urgently required.
As one solution, there is considered a method in which freon cleaning is replaced by water cleaning, for the removal of residual flux, and recently, water-soluble fluxes have been investigated.
As the water-soluble flux, an inorganic salt type flux composed of zinc chloride, hydrochloric acid and the like, and an organic salt type flux comprising an amine hydrohalogenide and glycerol, polyethylene glycol or the like are used. These conventional fluxes, however, are defective in that the activity of removing an oxide on the metal surface is too strong, and if the cleaning is not thorough, corrosion occurs. Moreover, when these conventional fluxes are used for solder paste, the viscosity is too low and a good printing cannot be obtained. Accordingly, the development of a novel water-soluble flux is urgently required in the art.